當對數以原始數x10a型態呈現,即對數值+a
即 n < (log3.14x10-3)-3 < n+1
n < (log3.14)-3 < n+1
0<log3.14<1
故 n < -2.多 < n+1
又n 為整數, 故 -3<-2.多< -3+1=-2
n=-3